Allelopathic potential and systematic evaluation of secondary compounds in extracts from roots of Canavalia ensiformis by capillary electrophoresis

Abstract

Organic extracts were obtained from roots of Canavalia ensiformis and evaluated for allelopathic potential on the germination of the weed seeds: Mimosa pudica, Cassia tora and Cassia occidentalis showing a strong allelopathic potential. After that, a systematic study of these crude extracts was made using specific protocols developed in capillary electrophoresis (CE) in order to determine some classes of secondary metabolites. Capillary electrophoresis protocols were highly specific, which makes it possible to identify 5 classes of compounds using the same crude extract samples and analyze them fartly. Some of the compounds identified show activity in the inhibition of seeds germination.Keywords: allelopathy; capillary electrophoresis; Canavalia ensiformis; roots. organic extracts are carried out using one or more chromatographic techniques. The use of these techniques for analysis of a great amount of compounds can be very time-consuming, though, especially when it involves complex mixtures like plant extracts [6][7][8][9][10].Capillary electrophoresis (CE) is a microanalytical method that has become an extremely advantageous technique for the separation of many compounds in phytochemical analysis, mainly because it provides the possibility to inject crude extracts without previous purification or separation of the active compounds. CE provides advantages in terms of speed, high efficiency, low cost and simplicity. This technique requires small contents of electrolyte and sample, no solvents and consequently produces small amounts of residues [6][7][8][9][10].Capillary electrophoresis is performed in columns with capillary dimensions (25-75 µm of internal diameter and 375 µm of external diameter). The capillary is filled with an electrolyte solution, immersed in two reservoirs containing the selected electrolyte and submitted to high voltages. Samples are injected in the capillary by the controlled application of either voltage or pressure during a period of time. The compounds are separated into the column and detected by a detection system. [11].Studying the physical-chemical interactions between the analytes and the electrolyte medium components, TAVARES et al [12] drawing several analytical protocols to phytochemical analyses that provides an instantaneous profile of the plant secondary metabolic status at the time of examination. Due to the versatility of CE technique it is possible to separate and identify specific classes of plant constituents just by using a single capillary column, selecting a proper electrolyte and pH. The procedure for analyses using the protocols is simple and means only injecting crude extracts without previous purification under specific conditions (pH, electrolyte, wave length) that facilitate the ionization and separation of a specific class of compounds.In this work we assembled capillary electrophoresis protocols to carry out a systematic evaluation of organic extracts from Canavalia ensiformis roots. It were separated and identified five classes of compounds: flavon...

Potencial alelopático e identificação dos metabólitos secundários em extratos de Canavalia ensiformis L.

“…Para verificar a existência de compostos no extrato da parte aérea de C. ensiformis, foram selecionados alguns padrões, já identificados em estudos anteriores, com a mesma espécie, e comparados com os presentes na amostra: flavonoides (kaempferol, quercetina, rutina e naringina), ácidos fenólicos (ácido ferúlico, ácido clorogênico e ácido cafeico) e ácidos carboxílicos (ácido cítrico, ácido malônico e ácido aspártico) (Santos et al, 2007;Mendonça, 2008).…”

“…Os metabólitos secundários ácidos fenólicos (ácido clorogênico, ácido ferúlico, ácido cafeico), flavonoides (rutina, naringina, kaempferol, quercetina) e ácidos carboxílicos (ácido malônico, ácido aspártico, ácido cítri-co), identificados por meio da técnica da eletroforese capilar, foram encontrados nas raízes de C. ensiformis (Santos et al, 2007). Desses compostos, o ácido clorogênico, ácido ferúlico, rutina, naringina, kaempferol e ácido cafeico apresentaram maior inibição de germinação de plantas daninhas.…”

Determination of polyamines in organic extracts from roots ofCanavalia ensiformisby capillary electrophoresis

“…[1,2] Canavalia is relatively free from diseases, pests and weeds, causing this plant to be an interesting object for research. [2] The allelopathic potential of extracts obtained from leaves [3] and roots [4] of Canavalia ensiformis in different organic solvents was evaluated early in our group using bioassay procedures. These extracts were applied to Petri plates that contained common weed pests.…”

CONTROLE EM PÓS-EMERGÊNCIA DE Conyza canadensis e Conyza bonariensis COM EXTRATOS DE Canavalia ensiformis

“…Observou-se ainda neste trabalho que ocorre um aumento na porcentagem de inibição de germinação de sementes das plantas daninhas utilizadas no trabalho ao se utilizar a mistura das substâncias citadas quando comparado aos bioensaios utilizando soluções de apenas um dos Podemos inferir com isso que é o efeito sinérgico das quatro substâncias presentes nas folhas de feijão-de-porco, ácido clorogênico e ácido p-anísico o responsável pelo controle de C. canadensis e C. bonariensis. Outros tecidos vegetais de C. ensiformis, como sementes e raízes tem sido investigados por alguns autores, revelando também substâncias alelopáticas contra espécies de plantas daninhas (Mendes e Rezende, 2014;Santos et al, 2007;Santos et al, 2010).…”